It is known that a dispensing device, for example of the trigger type, comprising a container for a liquid to be dispensed and a dispenser head, requires a vent system which enables the internal ventilation of the container.
In fact, some liquids release vapors so that in the absence of a vent system they tend to build up inside the container, even provoking bulging of the same.
Some known types of dispensing devices contain a mechanical vent active only in specific functioning phases of the device, such as during the dispensing phase.
A dispensing device produced as described above is shown, for example, in document WO97/38796. Another device produced as described above is shown in document EP-A1-1199105, in the name of the same Applicant.
The need has therefore arisen to produce dispensing devices equipped with means of ventilation that are always active, that is able to perform their ventilation function whatever the functioning configuration of the device.
Examples of such dispensing devices are shown in documents EP-A1-0729901 and EP-A1-0891228.
However, such solutions cannot be used in dispensing devices of the type comprising a container and a dispensing head.